The present invention relates to a connecting device and a bearing bar consisting of a tube having such a connecting device at each of its two ends. The connecting device may be used to join horizontal and vertical scaffolding elements. The connecting device consists of a bearing head and a clamping device and is of such a design that its top edge lies in a plane with that of the tube attached thereto. In addition, the connecting device has bolts for a non-positive connection with overlying elements suspendable thereover. These constructional features of the connecting device allow the overlying elements, which have holes or eyelets to be pushed over the bolts of the bearing bar for suspending in the scaffold, to be placed close up to the post elements, so that virtually no gap between an overlying element and a post element is formed. Moreover, the length of the bearing bars may be dimensioned in such a way that frame scaffoldings and modular scaffoldings can be combined as a result of an identically adjustable axial spacing of the pair of posts of a modular scaffolding with respect to the axial spacing of a frame scaffolding.
With increasing occupational safety regulations, work scaffoldings become more and more important. In addition to rapid assembly, scaffolds are required to meet high safety demands. These requirements are summarized in DIN 4420.
Work scaffoldings are categorized into two types of scaffoldings, the so-called frame scaffoldings and the so-called modular scaffoldings. More specifically, the frame scaffoldings consist of vertical tube framing elements connected with directly stiffening overlying elements and with rail and vertical diagonal braces.
Unlike the above, modular scaffolds have single tubes as vertical posts, which have regularly spaced holding means to suspend bearing bars, as well as longitudinal and diagonal braces. Using the bearing bars which, e.g., have a connecting device according to FR-A-2,288,199, two posts at a time are connected in pairs, and each pair of posts is stiffened in a longitudinal direction by means of longitudinal braces, suspendable overlying elements and diagonals.
Likewise, when suspending the overlying elements, there are primarily two modes of attaching which do not depend on the type of scaffold. In one mode of attaching, the overlying elements have holes or eyelets which are pushed over bolts on the bearing bar, thereby forming a non-positive connection between bearing bar and overlying element. In another mode of attaching, the bearing bar has a preferably continuous groove, into which the hooks or claws attached to the overlying element are suspended to establish connection between the overlying element and the bearing bar.
In addition to safety, the ability of combining both types of scaffolds plays an important role, making arrangements more flexible and allowing complicated constructions to be scaffolded more easily. In this context, it is advantageous to have conformity of the axial spacing of the pair of posts of a modular scaffolding with the fixed axial spacing of the vertical tube framing elements of frame scaffoldings.
To date, such combining capability has only been possible with those scaffoldings where the overlying elements have hooks or claws suspended in the groove of a bearing bar, because in these scaffoldings the axial spacing of the pair of posts of the modular scaffolding may be identical with the axial spacing of the vertical tube framing elements of a frame scaffolding.
With those modular scaffoldings, however, wherein the overlying elements have holes or eyelets pushed over bolts on the scaffold bar in order to be suspended in the scaffold, combining with frame scaffoldings up to now has only been possible using great expenditure, particularly for that reason because the bearing bar, and thus the axial spacing of the pair of posts of the modular scaffolding, had to be larger than the axial spacing of a corresponding frame scaffold. As an additional drawback, a relatively large gap had been formed between the post element and the outer edge of the overlying element, representing a corresponding safety risk.